That's all I can get here in Texas is the 10% ethanol crap. I would love to pay an extra $0.25 a gallon for straight gas, like when we go through other states sometimes

 

So, update.

I've replaced the sending unit, pump, and washed the tank out as best I can. It runs great now, but it always does with a fresh pump!

I'll keep an eye on it, and update this thread if and when future problems arise

 

C. Red, non ethanol in SC is more like $0.30-0.35 more per gal. The people with chain saws, lawn mowers, weed eaters, gas generators, and any small engine with a carb love to use non ethanol gas so at the beginning of a season, the engine will start without dislocating a shoulder. But F-150 and Silverado owners also use it because they say they get better gas mileage. The good news is: if you run the gas out frequently such as a daily driver, you don't need to worry. The eth. gas doesn't have a chance to separate and start clogging things up. It's only when it sits for a while that it becomes a problem. The best example is a gas generator ! When a hurricane is coming, you want it to start first pull even though it has been sitting in a hot garage!
Here in SC it is 10% ethanol, but some legislators would like to go to 15%.

 

So, with probably less that 15 miles on the new pump, it's back to running bad. Haven't put a fuel pressure guage on it, but I know the symptoms, and it's a bad fuel pump.

I'm pretty pissed at the thing, I don't want to look at it, let alone work on it. And I found a nice 4runner on Craigslist, that if I can get the guy down on price enough, I'm gonna get and send the blazer across the scales.

 

Is it possible to build a jig to test the pump outside of the trunk?

 

It sounds like your drawing up divorce papers at this point but if you get another surge of energy to work on this:

How many fuel pumps have you put it and what were the brands?

While the pump is running you should check the quality of the power at the leads going into the pump. I don't remember how close you can get with everything in place. All connections should be soldered and shrink wrapped. The ground should be clean and tight.

Try to rule out any restrictions in the fuel circuit looking for kinked lines, do the complete pressure test and checking pressure while the truck is running (be careful with all of that high pressure gas). Has the regulator ever been replaced?

If your done with this then ignore these questions, If not I'll try to help.

George

 

I recall a thread in which the OP reported that the problem was that when the tank was reinstalled with the new pump, the lines would get kinked due to clearance issues with the underside of the body. Perhaps it is kinks in the hose restricting flow or kinks reducing flow so that that pump motor works excessively hard and wears itself out. Just a thought.

 

Man, if it's kinks in the fuel lines, I'm gonna feel like a doofus!

It's destroyed its third Delphi pump so far since January

 

Also I think the idea was that the OP in that thread I was remembering was that he left some extra length in the lines perhaps thinking that might be a good thing but actually that is what led to the kinking.

To prevent kinking is one of the reasons I've considered cutting out a panel from the bed of the cargo area to get at my pump if (when?) it ever goes bad.

 

Did some electrical troubleshooting today, to rule that out.

With the truck running, 13.5 at fuel pump + to frame, battery is 14.5, so 1v drop.

I turned on every bit of electric load I could, fuel pump + to frame was 12.0v, battery at 13.0v so the same 1v drop.

Fuel pump - to frame was less than one ohm, can't remember exactly.

Across the fuel pump connector, truck running, was 0.01 volts. So that seems acceptable.

Can anyone else think of other electrical woes? Guess next step is to drop the tank, and visually inspect for kinked fuel lines